I want this box to work on WiFi only. So far I have been able to get ethernet working (dhcp, default) and the WiFi configuration (static) works only when the ethernet cable is connected. I've done all configuration with Xbian-config command UI.

So at some point I can ssh with two different IPs. If I unplug the ethernet cable both interfaces go down. If I boot without the cable, WiFi does not start.

I tried configuring network bonding just for the sake of testing (see this), but it didn't work.